That kind of distortion may be removable via an adjustment somewhere. It was normal for CRT equipment to develop that kind of distortion to some degree - as components aged, even when it was rotated/moved. So there are usually adjustments to cancel all those kinds of distortion out.

I can safely say there is nothing magnetic nearby. Just more TE. I have to get up the energy to open it up--wait, should probably do some reading in the service manual first. I was on vacation last week and am happy to be back to work to get a vacation from my vacation. I am playing with it in between doing things for work.

I do have the service manual downloaded so I can see if there is anything in the manual about it. That will be fun, moving it around to open it up. It surely qualifies as a boat anchor.

Found one on the "dock of the bay" for $499 parts only, but did a best offer, and got a sizable discount, nearly half off. It was a risk, but...Since it boots from the 1MB CF Card, and it wasn't booting, I popped in a good booting one, with the latest firmware onboard, and shazzaaam. Like new.

Haven't been posting but you guys know I have a soft spot for old HP gear. But what kicked-off this spate of spending was the recent Frequency Measuring Test. I brought up my Cesium beam and had a problem which Corby (great time-nut, everyone should have a Corby) helped me fix quickly by sending me a -2500V power supply for $30. Well in the process I started thinking about building a Dual Mixer Time Difference test set for doing ADEV work on oscillators. So in looking around I found 2 x HP 10811 Oscillators for $65 per with shipping. That's an OK price but they have to have good stability to be a deal...

So then on scanning Craig's list for old HP equipment to pull the 10811's out of, I found an HP 8770S/A 120Mhz arbitrary wave generator for $45. This has an 10811 in it standard whereas a lot of HP equipment needs option 01 or 001 to signify that it has a high-stability generator. Brought the 8770 home with the intention of gutting it for the oscillator and attenuator but tested it and it works great! So now I might keep it for a while as I could use a net 50Mhz or so arbitrary generator. I did some VB code to generate the waves and they are pretty cool for the age.

Then in looking for another 10811 as I need three for the test set (not mandatory) I found an HP 8350B with an 83525A .01 - 8.0 Ghz sweeper for $135 plus shipping. Not wanting it to get away and fully expecting the price to take off in the next day or so, I offered $150 with local pickup and no returns and the gentleman took it! I think it's a deal. I brought it home, picture attached, and it is beautiful, works great, calibration was good to 2017, etc. Love it. I wanted one for a while to be able to test higher frequencies with my 8566B. This is my new darling. Nice and quiet as well.

Anyway, that's all for now. Best of luck bin-diving as we go through the holidays.

Jerry

Anyway, Every time I say I am now "fully configured" I think of something else I "need."

Then in looking for another 10811 as I need three for the test set (not mandatory) I found an HP 8350B with an 83525A .01 - 8.0 Ghz sweeper for $135 plus shipping. Not wanting it to get away and fully expecting the price to take off in the next day or so, I offered $150 with local pickup and no returns and the gentleman took it! I think it's a deal. I brought it home, picture attached, and it is beautiful, works great, calibration was good to 2017, etc. Love it. I wanted one for a while to be able to test higher frequencies with my 8566B. This is my new darling. Nice and quiet as well.

What I "need" now is a power meter, like a 436 or 437 with cable and sensor. So I'll put that out there if anyone has one that is surplus to their needs or knows a source. I've been hesitant to purchase one off eBay as I hear that the sensors are generally bad, burned out, stressed, etc. I'm sure that person who told me this is painting with a broad brush though. The 8350 setup can use an external meter for leveling to .1dBm accuracy. So not that I need that level of accuracy just that if it can be done, why the heck not? I've seen the meters for less than $75, actually have a local here with a 436 for $15 that powers on so I might pick that up a scrounge for a sensor and cable.

Now that I have el sweeper, I can test all these filters and amplifiers I've acquired to a new level of precision. I'll have to figure out how to use it with my 8566B if possible as a tracking generator. I have external mixers, directional couplers, etc so worst case I could just put the spectrum analyzer in peak hold mode.

What I "need" now is a power meter, like a 436 or 437 with cable and sensor. ...I've been hesitant to purchase one off eBay as I hear that the sensors are generally bad, burned out, stressed, etc. I'm sure that person who told me this is painting with a broad brush though. ...Jerry

I've had close to a dozen HP 8484A sensors from eBay over the last 5 years pass over my workbench and have had pretty good luck. I can't remember receiving any from eBay's "used" category being bad. I've also bought a few listed under "parts/repair" as unknown that also checked out OK. In fact one was listed as "parts/repair - would not zero". After fixing the cracked plastic clip that holds the sensor cartage cartridge wires to the PCB it zeroed and calibrated fine. Yes you would need to have it re-characterized if you move or mess with the sensor cartage cartridge.

I like the 8484's because they go down to -70dBm and you can use an18Ghz 30dB attenuator to bring it up from it's max -20dBm to +10dBm when needed. You would also need to purchase the 50Mhz calibrated 30dB attenuator to perform meter calibration. You can't use the 50Mhz for other frequencies so you would need a separate broadband 30dB attenuator for power levels up to +10dBm across the sensors frequency range.

When purchasing one of the 84XX series I would look under the 'used' category for one with the calibration chart attached. You should be able to pick up a working 8484A for around $100.00. I've run power level tests from the same signal source on several 8484A (from eBay) against their respective calibration correction charts an found they all tracked pretty close across their frequency range when using their correction coefficients. So it seems like if it is working the calibration chart is still relevant.

You may also lean toward the 437 since you can store the calibration coefficients in a frequency lookup table - some added convenience.

I found a 437 last night with cable and sensor and after two offers that I've been turned down, I might just bite the bullet and buy the efing thing now. I mean come on, why would someone put BO if they're only going to take the buy it now price? Don't they know there are bottom feeders out there that need to be fed too?

The other question I have is how does one of these meters compare to a RYO using some of the AD chips? If you use a good ADC to read the DC output and calibrate it against a table, I would think some of the AD5513 and the others, can't remember the number(s), would also give them a run for the money. Wouldn't calibrating an AD5513 board with a scope and 50ohm standard be pretty accurate? Would also need multiple frequency tables I guess. The output signal would have to be amplified to the correct scale to feed the 8350 system so maybe that's a lot of work for so-so results.

Another question here, and this might not be the place, is how do these meters compare to an 8566B SA which is good to .2dBm, I think? I'll have to pull the datasheets. I think the 8566B goes to +30dBm, I know my Advantest SA does which is a little higher than most of the sensors on the 437 system. So do I really "need" the 437? ha, maybe I should move this to the TEA forum...

... I mean come on, why would someone put BO if they're only going to take the buy it now price?Jerry

eBay has recently changed their selling interface & structure. As in the past they always have specials where you can 'list' for free but are required to pay a percentage when the item is sold. Now when you choose to list, you must choose to accept Best Offer solicitations or else there is an additional opt out charge (i.e. sell with a firm price). It doesn't mean you have to accept these BO's - you just have to be open to these offers. So if you want to 'list' for 'free' you have to take the BO option. It's a stupid and petty requirement from eBay - they still make plenty with their seller fee.

...The other question I have is how does one of these meters compare to a RYO using some of the AD chips? ...

...Another question here, and this might not be the place, is how do these meters compare to an 8566B SA which is good to .2dBm, I think? ...Jerry

I think the AD chips may be limited on frequency range and repeatability. They are a good value proposition for the price. There are rf power meters modules/units sold on ebay utilizing these chips. If I was going to rely on one I would characterize it against an HP power meter and then resell the HP if you are happy with the performance of the AD based measurements.

On the HP 8566/8 you may be confusing power resolution with its accuracy/repeatability. The HP 436/7 with its power sensors are significantly more accurate and repeatable. The RF path through an SA goes through RF switches and variable RF attenuators which creates mechanical repeatability issues that are not present in the 437 power meter. The SA is more a 'qualitative' instrument like an o-scope.

I've had close to a dozen HP 8484A sensors from eBay over the last 5 years pass over my workbench and have had pretty good luck. I can't remember receiving any from eBay's "used" category being bad. I've also bought a few listed under "parts/repair" as unknown that also checked out OK.

The 8484A is a diode sensor. The thermocouple sensors like 8481A and 8482A may very well be different. Despite their higher maximum power levels, they appear to die more frequently. Probably because they are more sensitive to overloads. And there appears to be almost no chance of repairing them given the lack of spare parts and special skills available if the thermocouple is blown.

I've had close to a dozen HP 8484A sensors from eBay over the last 5 years pass over my workbench and have had pretty good luck. I can't remember receiving any from eBay's "used" category being bad. I've also bought a few listed under "parts/repair" as unknown that also checked out OK.

The 8484A is a diode sensor. The thermocouple sensors like 8481A and 8482A may very well be different. Despite their higher maximum power levels, they appear to die more frequently. Probably because they are more sensitive to overloads. And there appears to be almost no chance of repairing them given the lack of spare parts and special skills available if the thermocouple is blown.

That's a good point. I think the thermocouple is also more sensitive to shock.

I would agree that the 8484A are pretty sturdy. Even though they have a max of -20dBm; I believe they can tolerate +30dBm for short periods. I probably wouldn't deliberately chance it.

You bring up a good point regarding the themocouple sensor being a bigger risk. I can't speak for the 8481/2A's however I have had at least three 8481D's from eBay without any trouble - the "D" version might be diode sensors also.

After fixing the cracked plastic clip that holds the sensor cartage wires to the PCB it zeroed and calibrated fine. Yes you would need to have it re-characterized if you move or mess with the sensor cartage.

You may also lean toward the 437 since you can store the calibration coefficients in a frequency lookup table - some added convenience.

I've had close to a dozen HP 8484A sensors from eBay over the last 5 years pass over my workbench and have had pretty good luck. I can't remember receiving any from eBay's "used" category being bad. I've also bought a few listed under "parts/repair" as unknown that also checked out OK.

The 8484A is a diode sensor. The thermocouple sensors like 8481A and 8482A may very well be different. Despite their higher maximum power levels, they appear to die more frequently. Probably because they are more sensitive to overloads. And there appears to be almost no chance of repairing them given the lack of spare parts and special skills available if the thermocouple is blown.

There is a company on ebay that will fix 8481As or sell you a fixed one for around $450.

Expect any 'untested' 8481A or 8482A to be broken. Even those that zero may be compromised. I've returned two 8481As - the first because it failed on SWR though it would zero and measure power, the second because although it would zero, it didn't actually measure power. I did however manage to get a working 8482A. I have an 8484A as well, but it tends to drift.

If someone says "for parts or best offer" and then you ask them if it powers up and they tell you it does, but then it doesn't power up when you get it, instead it blows a fuse.. who is right? What to do?

If someone says "for parts or best offer" and then you ask them if it powers up and they tell you it does but they cant test it further but then it doesn't power up when you get it, instead it blows a fuse.. who is right? What to do?

Then you make a claim with the seller and tell him it is not as described and make arrangements for a lower price (partial refund) or return it for a full refund. Most sellers will agree to a partial refund in my experience.

Logged

There are 3 kinds of people in this world, those who can count and those who can not.

If someone says "for parts or best offer" and then you ask them if it powers up and they tell you it does but they cant test it further but then it doesn't power up when you get it, instead it blows a fuse.. who is right? What to do?

Then you make a claim with the seller and tell him it is not as described and make arrangements for a lower price (partial refund) or return it for a full refund. Most sellers will agree to a partial refund in my experience.

Then you are lucky. 'For parts' means what it means. Unless the description says 'powers up' ofcourse. However 'powers up' doesn't always have to be a good thing. If it powers up then there is usually a more complicated error. A power supply is easy to fix.

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There are small lies, big lies and then there is what is on the screen of your oscilloscope.

After fixing the cracked plastic clip that holds the sensor cartage wires to the PCB it zeroed and calibrated fine. Yes you would need to have it re-characterized if you move or mess with the sensor cartage.

You may also lean toward the 437 since you can store the calibration coefficients in a frequency lookup table - some added convenience.

What is the assumed meaning of 'cartage'?

Sorry for the spelling error. I meant to say 'cartridge'. The front end after the RF connector that holds the actual sensor/diode in the case of the HP 8484A.

I thought the 'D' power sensor models were the diode type? for instance 8481d, 8482d, etc.

Thanks for all the input. This is all complicated but I'm starting to understand what I need.

The 8484A is diode sensor; so their is at least one 'A' model that is an exception to a "D" naming convention. It's my understanding that thermocouple sensors don't have sensitivity to reliably measure below -30dBm. So if the lowest range on the datasheet is significantly below -30dBm (e.g. -70dBm) it's probably a diode sensor. However, to confuse the issue more, there are some HP sensors that use both both diode and thermocouple to get a much wider range. I believe this is only on newer models (E-series) that have the correction coefficients stored internally in each sensor. I don't think these sensors are backward compatible with the HP 436/7/8 power meters.

As a side note the 8484A and 8481D seem almost identical except that the 8481D is smaller. Maybe some one knows what the differences are? Again I've had pretty good luck on both models but as they say "your mileage may vary"....

thanks again. still debating. Now I'm thinking I want a 438 instead of a 437. I found sensors in the 150 range, cable in the $50 range and I can get a 438 for around 150 or less. So for 350 I can get one channel configured and then work on the second at a later date. The power sensors look like the are very band and range specific. If doesn't look like many have more than about 50db of range. So it looks like you have to have a stack of attenuators.

The problem I have is after picking up the 8350 for a song, I find it hard to pay double for a power meter, or more. I pulled the plug-in out of the 8350 today and it is absolutely spotless. Nice and clean - almost polished - rails. I doubt it was used much. The liquidator that sold it really doesn't have much equipment so it must have been a fluke.

I posted another thread asking if I can somehow mix it to use as a TG for my 8566b second band from 2.0 to 5.8Ghz. I can use it with max hold, of course.

thanks again. still debating. Now I'm thinking I want a 438 instead of a 437. I found sensors in the 150 range, cable in the $50 range and I can get a 438 for around 150 or less. So for 350 I can get one channel configured and then work on the second at a later date. The power sensors look like the are very band and range specific. If doesn't look like many have more than about 50db of range. So it looks like you have to have a stack of attenuators.

Mini-Circuits will sell you a stack of attenuators... I have a K1-UNAT+ - good to 6GHz. I tend to keep the 30dB attenuator on the 8484A.

And Orin, nice to hear from you, hope all is well up north. I'm still taking good care of your Geller standard and will repay the favor someday I hope. Playing with any 3456s lately? I still have one in the garage a patient gentleman sent me to fix about 18 months ago and though I said "at my convenience" I think this is pushing it and I should get a move on. They are fun to fix on a rainy day.

And Orin, nice to hear from you, hope all is well up north. I'm still taking good care of your Geller standard and will repay the favor someday I hope. Playing with any 3456s lately? I still have one in the garage a patient gentleman sent me to fix about 18 months ago and though I said "at my convenience" I think this is pushing it and I should get a move on. They are fun to fix on a rainy day.

Jerry

Hi Jerry,

All is well up here - at least after getting a new furnace on Monday. Glad that the Geller is still alive and well and has a good home. I haven't been doing anything with the 3455 or 3456s. I should get back to that nanoprocessor FPGA project.

OK, I've had a run of good luck. I picked up two 3586 Selective Level Meters for $50 per. These are basically a radio that was used for testing channelized voice on T1 and other lines. I can't remember what the voice technology was called but it was still around in 2001 when I was at cisco. Very accurate for testing filters, etc. up to 30Mhz with some limitations above 20Mhz. There are a number of boxes that look like this including the 3336 Synthesized Level generator, 3325 Synthesize/ Function Generator, 5325 Universal Counter, and I think one or two others. I have one of each or so, ok, two of each or so. I've had a 3586B that I've used for the Frequency Measuring Tests but the more desirable of the 3586's are the 'C' model as it has a true 50ohm input. The two I bought today for their Option 004 ovenized 10811 oscillators are an 'A' and 'C' with the 'C' being in the better shape. It has some hanger rash on the cases but not real bad. You can see the front panel is in pretty good shape. The issue with this line of products from HP were the white line across the front under the LED display always discolored. But it can probably be fixed with the peroxide and sunlight trick.

The 'A' unit didn't fully power on but the fans started and it went into standby, but no lights, etc. Probably a power issue. The 'C' model powered up with an error. I wasn't going to fix it but when I opened it up to gut it, it was so absolutely gorgeous on the inside I thought I would take a crack at fixing it. Turned out to be the fractional N VCO so I swapped it with one from the unwanted 'A' unit and off it goes. Works perfectly. I tweaked the oscillator to my Cesium beam and ran if for a couple of hours and I'm happy with it. I'll put it on top of my 'B' unit and decide which to use in the future.

So take a look at how these are built. The HP 8566B and 8568B spectrum analyzers were built the same way with bolt-down panels holding the cards sliding into a frame. These units weight a ton. The 8566B I know exceeds 140lbs with the two units. This thing has to be over 60lbs. It's a pain to get the cards out because of all the bolts but it is solid. After removing the bolts you pull on the silver spindles to remove the cards